Significant Fuss And Ways To Mitigate Moisture – A Catastrophe to mechanism of PCB Assembly

By | Date posted: | Last updated: April 8, 2022
pcb-assembly

This article gives a clear steer as to the issues related to moisture in printed circuit board. It is a precise write up on reducing the level of impact of moisture on any type of printed circuit board. Right from the Material melds, pcb layout, prototyping, PCB engineering, assembling to packaging and order delivery stage, the effect of moisture in PCB fabrication should be taken care of to avoid damages and other issues in the functioning of the PCB. Furthermore, let’s take a dip into significant measures implemented for controlling the humidity level during the process of lamination, at the time of PCB assembly and controls implemented during storage, packaging and shipping of order.

Rigid/Flex printed circuit board assembly, cable harness, box-build assembly or wire harness PCB assembly are fabricated with varied types of material meld that well suits the attributes required for strong mechanical and electrical capability in electronic products that are used in all dominant sectors globally. Be its need for high frequency with low impedance, compact, durable, high tensile strength, low weight, multiple feature, temperature control or resistance to humidity, the PCB is categorized as single layer, double layer or multi layer depending on the complexity of the circuitry. Among all the serious concern that should be taken care from the initial stage of PCB manufacturing, humidity or moisture is the prime element that becomes the cause of creating a room for electronic and mechanical disorders in the PCB operations.

How moisture can create a great fuss in printed circuit boards?

The moisture can forge ahead various defects in the PCB assembly by its presence in epoxy glass prepreg, diffused in PCB during storage process, absorption at the time of wet processes in PCB manufacturing, residing in the micro cracks or can make a home in resin interface. As the high temperature and vapor pressure go parallel with led-free mechanism in PCB assembly, it results in uptake of moisture level. Check out the guide on How to Protect PCB from Moisture in Outdoor Environments.

Along with the adhesive and cohesive malfunctions in printed circuit boards resulting in Delamination or Cracking, moisture can make the metal migration possible that can cause low impedance path with variation in dimensional stability. With more technical damages like reduction in glass transition aridity, rise in dielectric constant and many more, it results in lower speed of circuit switching and high level of delay in propagation times.

The major effect of moisture in PCB is, it reduces the degree of quality of metallization, lamination, solder mask and the process of PCB manufacturing at large. The limit of thermal stress goes in excess with the reduction of glass transition temperature due to the effect of moisture. Sometimes it also leads to critical short circuits with the effect of moisture ingress that results in ionic corrosion. The other common attributes to moisture absorption in the printed circuit board assembly includes Blistering or Delamination, increases the (DF) dissipation factor and (DK) dielectric constant, thermal stress on plated through hole and oxidization of copper.

Ways to mitigate moisture in PCB fabrication:

Whether the PCB fabrication uses simple or complex technologies, there are many operations in PCB engineering that requires a wet process and also removal of residual moisture. The raw materials used in PCB manufacturing need protection during storage, handling and tackling stress during PCB assembly process. A short guide to controls implemented at the time of various stages of PCB operation is addressed below:

1. PCB Lamination

Lamination is a dehydrating step in PCB fabrication as the cores and prepregs are stacked with bonding the layers into the laminate. The chief elements to control in the process of lamination is the degree of temperature, time taken and heating rates. Sometimes with low aridity, the steps are taken to decrease the magnitude of vacuum to lessen the chance of internal voids that attracts the humidity to get absorbed. So the degree of moisture can be well controlled with using gloves in handling the prepregs and that too from the edges. This reduces the cross contamination. Non corroding humidity indicator cards should have flexibility to resolve the humidity levels whenever required. The wash cycle of laminates should be of short duration with effective storage in a controlled environment which helps prevents the forming the pockets of humidity in laminates.

2. Post lamination processes and PCB assembly

After the drilling, photo imaging and etching operations in PCB fabrication, the moisture absorption rate is higher as it gets entrapped during the wet processes. The silkscreen cure and solder mask bake are steps that are processed to get relief from the entrapped humidity. This adds up to more effective in reducing the level of moisture uptake by minimizing the holding time interval between the steps and even keen in managing the storage conditions. By ensuring at the early stage of PCB lamination that circuit boards are sufficiently dry can help reduce baking operations after lamination. Also, using a high quality surface treatment to prevent cracks during drilling and removing the residue humidity by baking before the process of hot air solder levelling. The baking time should be kept by considering the decided level of moisture content, complexities in the PCB fabrication, PCB finish and adequate thickness required in the circuit board.

Thus, it is vital to get updated on the effect of moisture in PCB fabrication to avoid malfunction, damages and short circuit on the PCB with increasing the cost of rework as well. Researches are now upcoming with more advanced solution to control the element of moisture in each and every step in PCB manufacturing that saves time, energy and cost by using environmentally friendly PCB technologies.

Technotronix has a combined and extensive years of experience in PCB engineering, prototyping, PCB Making, assembly process and PCB fabrication. Having a strong customer base from different sectors, they have a well defined Fabrication Unit with the high tech tooling room. Our team of skilled engineers have experience in tackling and providing an optimum solution to any king of printed circuit board project. Here at Technotronix, we proffer high end customization to address the exact needs of electronics manufacturers. Be it lamination, drilling, prepregs, solder mask, through hole or any simple or complex process, we have stringent testing modules to avoid damages, defects in batch of production.

Please explore our PCB Assembly services. Feel free to contact us to get consultancy, quote or to get updates on our recent project. You can simply drop an inquiry to [email protected] or give us a call at 714/630-9200 to solve your queries.
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What are the Problems that need to be avoided In PCB Assembly Process?

By | Date posted: | Last updated: April 8, 2022
pcb-assembly-process

PCBs are an integral component of any electronic device be it a small toy or a sophisticated computer. Its complex interconnected components comprising of resistors, diodes, capacitors and more allow the device to work in tandem. In a sense it is like the “brain” of the system”. In high reliability systems particularly — such as oilrigs, space satellites and others failures can have devastating consequences. It is critical, therefore the PCB Assembly process is flawless and common mistakes in the assembly are watched out for.

Here are some of the factors to watch out for PCB Problem and solution:

Supply Chain Management

To be able to create high quality PCBs, the one thing that needs to be in order is the supply chain. It is important to check their availability, quality as well as price. Consistent ability to source the components is critical towards managing the manufacturing cycle of the product. You also need to be doubly sure of the quality of the products. Counterfeit components can have disastrous consequences on the product performance and your reputation. It is also important to check the lead-time of components especially as the volumes required increase. While you may take initial samples directly from manufacturers, remember to budget for lead times as volumes go up.

PCB layout

A common problem faced at the manufacturing stage is the nuances in PCB layout. While several designs may look good on paper, manufacturing them may be a different ball game. For example if the design has a large number of components positioned closely together, soldering them may be an issue. In case of a double-sided PCB, you need to make sure that the largest components are placed on one side. Essentially you need to make sure that the pcb layout is indeed viable at the manufacturing stage. If for example, holding down complicated parts requires them to be glued manually, it will add to your assembly time as also leave margins of error.

PCB Testing

A common problem associated with PCB Assembly, is that the testing is often done after the manufacturing. What needs to be done, however, is to design the test points as you conceive the design. There are in fact a whole lot of PCB Functional testing ensure that the PCB is functioning correctly.

Some of PCB tests include:

  • Micro-sectioning Analysis- Also referred to as Cross sectioning, this test helps to identify component defects as also a thermo mechanical failures.
  • Solderability Testing- This test helps test PCB pad solderability to ensure that the surface is robust so that the solder joint will be reliable. It also helps to determine if storage will lead to any effects on the solder components.
  • PCB Contamination Testing- This tests a number of issues such as corrosion and degradation. Very often handling, flux residues etc can lead to contamination which can in turn lead to part failure. The contamination analysis is known for its accuracy and precision.
  • Optical Microscopy- This tests the PCB for problems associated with soldering and overall assembly. The process is known for its speed as it involves using a high power microscope to check for improper construction.
  • X-ray Inspection- A Non-invasive test, this lays bare any surface and internal defects with ease.

A whole lot of PCB Challenges also emanate from the fact that increasingly components are shrinking in size and circuits are becoming more and more sophisticated. Therefore, all the more chances of defects in the assembly.

The challenges faced by failure analysts are therefore many, printed circuit board common problems such as:

  • Growing popularity of High-speed Printed Circuit Boards (HSPCBs) – These require boards that are made up of two or three materials that increase the chances of failure. Added to this is the fact that it requires pins and chip placed in a correct manner.
  • Lead-free Assembly Process- This requires high temperature and a traditional tin solder.
  • Hole Barrel Cracking- A lot of the failure happens on account of barrel fatigue because of the differential expansion of the copper plating and the printed board.
  • Conductive Anodic Filament- This is an electro chemical process that can cause leakage and a breakdown between conductors.

PCB Assembly therefore requires an effective root cause analysis to ensure that corrective action is taken so that the problem does not recur. In addition a detailed failure analysis ensures ways to improve the product as also to correct faults that may not have been noticed at the design stage.

Technotronix offers professional PCB Assembly services with 40 years of expertise. Our accurate PCB assembly process meets the quality standards, including ISO-9001:2015, RoHS, and more. You can rely on our PCB design tools that, in turn, lead to that perfect PCB Assembly. Our superior engineering capabilities mean that each board matches your exact requirements and technical specifications. If you have any questions or any requirements related to PCB assembly service, please feel free to contact us via email at [email protected] or call at 714/630-9200.

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Top 10 Reasons To Build Lead-Free And RoHS Compliant PCB Assembly

By | Date posted: | Last updated: April 19, 2023
pcb-assembly

The ROHS directive issued by the European Commission (EC) which came into effect from July 1, 2006 has brought about a significant shift in the PCB Assembly and Fabrication process. ROHS, which is an acronym for Restriction of Hazardous Substances was brought into effect for the purpose of drastically reducing the use of toxic materials in the manufacturing and assembly of electrical and electronic products. The ROHS directive specifically bans electrical and electronic products that contain more than specified levels of any of the six hazardous substances listed below

  • Lead
  • Mercury
  • Cadmium
  • Hexavalent Chromium
  • Flame retardant PBB
  • Flame retardant PBDE

The ROHS Circuit board came into law from July 1, 2006 and empowered EU member states to refuse electronic and electrical products that contained any of the above mentioned hazardous substances in quantities greater than specified.

Complying with the ROHS directive required a major shift in the PCB Assembly process. This is primarily because the ROHS directive requires organization involved in the PCB assembly process to ensure that none of the hazardous substances specified in the directive is used in any of the assembly process including board, soldering and component. For instance, organizations providing PCB Assembly services had been using lead based solder for decades, the new directive required them to shift their process to include lead free soldering in the design and assembly of Printed Circuit boards used in the electrical and electronic industry. Also most of the circuit boards manufactured till then were coated with a finish that included lead and tin which also needed to be changed to lead free to ensure compliance with ROHS standards.

It has now become even more imperative for organizations to build a PCB Assembly process that is not only lead free but also ROHS compliant. The reasons range from legislative to environmental as well as financial.

Top 10 reasons for a lead free and ROHS compliant PCB Assembly process:

  • If you are a PCB Assembly services provider supplying to the European Union, then you will need to ensure ROHS compliance in your assembly process in order to do business in the EU. This is because any electronic or electrical product entering the EU needs a Bill-of Material that is ROHS compliant as well as use of technology that is ROHS compatible.
  • Even if you do not have business in the EU, it is better to plan proactively to build a ROHS compliant, lead free PCB Assembly process since almost all major countries and states are already planning legislation that limit the use of hazardous and environmentally damaging substances in industrial processes.
  • The introduction of RoHS has helped reduced environmental waste especially in third world countries which end up being the dumping ground for most electronic waste.
  • Health and liability risk associated with working with lead have become a major reason why legislation has been passed restricting the use of lead in many industries. In the PCB assembly process, the health risk posed to workers during contact with solder paste is what has led the move towards lead free PCB Assembly. A lead free PCB assembly environment provides eliminates health risks to workers and reduces liability of organizations involved in the assembly process.
  • With the use of lead free soldering, PCB designers have been able to simplify the design of the board itself which is the primary reason for a significant breakthrough in the size of the Printed Circuit boards. Simpler pcb layout has made it possible for PCB manufacturers to assemble and fabricate smaller boards, something which they had been struggling to do before. The ability to assemble smaller printed circuit boards is what has led to the introduction of faster and smaller hand held devices like tablets and cell phones.
  • Another big reason for using lead free soldering is that it makes it possible to assemble printed circuit boards with fine, tightly packed pitch components such as those required in the semi-conductor industry.
  • A major concern regarding the use of lead free assembly has been the issue of reliability since there is no common standard governing lead free soldering. But these concerns have proved to be unfounded as statistics conclusively show a reduction in errors and customer complaints in the EU region since the introduction of ROHS standards.
  • Lead free soldering has made mass assembly of smaller and tighter Printed circuit boards much faster and cheaper than before. This has enabled organizations using ROHS compliant lead free assembly process to achieve significant cost savings.
  • In addition, companies using lead free, ROHS compliant PCB assembly process are able to use it as a big selling point while pitching to clients.
  • Being lead free and ROHS compliant also increases your ability to compete in a global environment.

TechnoTronix is one of the leading manufacturer of proven PCB layout and PCB assembly service to the electronics manufacturers. Our main strength lies in the extensive experience and skilled team of experts to build Lead-Free and RoHS Compliant PCB Assembly and manufacturing solution. To get more insights into RoHS circuit boards, You can drop an email to [email protected] or give us a call at 714/630-9200 to solve your queries or to get a quote

Steps to a successful PCB assembly for efficient PCB prototyping and production

By | Date posted: | Last updated: September 7, 2024
PCB Assembly

Printed circuit boards (PCBs) are the backbone of all electronic and many electrical devices, providing the essential foundation that enables these devices to operate at the desired standards. Over time, simple PCB designs have evolved into complex and sophisticated printed circuit boards that power an ever-growing range of advanced machines and equipment. As gadgets become increasingly integrated into every aspect of human life, the importance of printed circuit board prototyping becomes more critical than ever. In high-stakes applications, such as healthcare, where gadgets play a pivotal role, the margin for error is non-existent, underscoring the vital significance of PCB prototypes and assembly.

The process of assembling printed circuit boards, commonly referred to as printed circuit board assembly (PCBA), involves soldering electronic components onto a circuit board. It’s important to note that PCB assembly is distinct from PCB manufacturing. The manufacturing of a circuit board typically occurs after the design, prototyping, and testing phases have been completed. However, PCB assembly takes place both during the prototyping phase and after the circuit board has been manufactured. This dual-stage process ensures that the final product meets the required specifications and functions correctly.

There are some items critical for assembling a Printed circuit board, these include

  • Circuit board
  • Electronic components for soldering
  • Soldering equipment
  • Materials such as solder paste and wire
  • Testing equipment

The most important PCB Assembly Process Steps:

  • Drawing up an Assembly Diagram
  • Adding Solder Paste
  • Component placement onto board
  • Board Reflow
  • Inspection
  • Final Assembly
  • Cleaning

Create a PCB assembly design

The first and most important step in printed circuit board assembly as well as manufacturing is the design of the PCB; it is like a pictorial road map that guides you to where each electronic component should be located on the circuit board. Assembling a circuit board is virtually impossible without a PCB assembly diagram; at best you will be able to create a low-quality PCB board prototype that is likely to fail most quality tests and will need considerable remaking to ensure it meets quality and performing standards. Printed circuit board Assembly diagram will accurately capture what components are required for assembling, their arrangement on the circuit board and how they will connect with each other for best performance. Check out the guide on How is Circuit Board Prototyping best option for innovative PCB design.

Applying Solder Paste

The actual process of PCB assembly starts with the application of solder paste to board with the help of stencils that are customized based on final product application. It is important to ensure that the circuit board and the stencil are facing the same direction and that the solder pads on the circuit board are fully aligned to the stencil cutouts. Make sure the stencil stays in place while you apply the solder paste.

Assembling the Components

Component Assembly can be done either by hand or with the help of a machine. The Machine Assembly of the circuit board can be done in two ways,

  • Surface Mount Assembly
  • Through-Hole Assembly

Surface mount assembly is generally used when small components need to be directly placed on the surface of the circuit board. These machines can mount all the components within minutes greatly increasing the speed and efficiency of the prototype PCB Assembly process.

Larger components like LED’s and capacitors on the other hand need to be soldered onto the circuit board using through-Hole Assembly process wherein they are manually placed on the circuit board. It is only after visual inspection has been done to ensure that each component is being placed on the right pad before soldering it in.

Board Reflow

After soldering the components onto the circuit board is completed, they are then passed through the reflow oven to bond the components with the circuit board mechanically. This ensures that the components are firmly connected, electrically and mechanically to the circuit board and to each other.

Inspection post Board Reflow

Post reflow inspection with the help of pinhole cameras helps ensure that the connections between the components are placed at the right locations.

Final Assembly

Final Assembly of printed circuit board is done to place any remaining small components as well as repairing and soldering of any misplaced components or electrical connections.

Cleaning

The last process in PCB assembly involves remaining flux from the finished printed circuit boards. New technologies like the aqueous system have made it possible to remove solder paste and flux from board without using chemicals harmful to the environment.

Conclusion
Prototyping is a vital step in any product development process. PCB prototyping service is particularly crucial, as different applications require various types of PCB assembly. Without assembling a prototype to conduct an actual functionality test, you risk ending up with a suboptimal product. In the past, printed circuit board prototyping was often costly and time-consuming, primarily because the assembly process had to be outsourced. However, advancements in technology have now made it possible to conduct circuit board prototyping on-site, making the entire process significantly faster and more cost-effective. This has streamlined the production of PCB prototyping boards and enhanced the efficiency of the prototyping phase.

Technotronix is an ISO 9001-2015 certified with having RoHS compliance PCBA and PCB prototyping expert. Contact us for custom and quick turnaround PCB assembly services for your electronic product at [email protected] as, we are just a click away on the internet freeway!

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